Apparatus for removing ink particles from paper products

ABSTRACT

A process and apparatus for removing ink particles from an inked paper product which includes a conveyor for conveying the paper product along a path, the conveyor being constructed of a semi-permeable material that passes the ink particles while retaining the paper product. Vacuum boxes are positioned proximate to a first side of the conveyor for establishing a pressure differential across the conveyor and across a first segment of the path to draw the ink particles from the paper product through the conveyor. Shower heads on a second side of the conveyor directed a liquid toward the conveyor and on to the paper product as the paper product is advanced along the second segment of the path. Blocking members are positioned on the first side of the conveyor opposite the shower heads for substantially preventing the establishment of a pressure differential across the conveyor and across the second segment of the path and for preventing flow of liquid and ink particles through the conveyor across the second segment of the path.

This is a division of application Ser. No. 703,950, filed Feb. 21, 1985,now U.S. Pat. No. 4,680,088.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method and apparatus for removing inkparticles from paper products so that the paper products may berecycled.

2. Description of the Prior Art

Various processes and apparatus have been used to de-ink paper productsso that the paper products may be recycled for further use. These knownmethods and apparatus use a series of stages in which the paper productis repeatedly washed. However, such devices have various disadvantages.In particular, there is a need for much space in setting up theapparatus and performing the method. In addition, known processes andapparatus contain other inefficiencies and complexities in set-up andoperation.

Accordingly, it is an object of the present invention to provide aprocess and apparatus for de-inking paper products which does notrequire much space.

It is another object of the present invention to provide a process andapparatus for de-inking which is simple and efficient in set-up andoperation.

Additional objects and advantages of the invention will be set forth inthe description which follows, and in part will be obvious from thedescription, or may be learned from the practice of the invention. Theobjects and advantages of the invention may be realized and obtained bymeans of the instrumentalities and combinations particularly pointed inthe appended claims.

SUMMARY OF THE INVENTION

To achieve the foregoing objects, and in accordance with the purposes ofthe invention as embodied and broadly described herein, a process isprovided for removing ink particles from an inked paper productcomprising forming a slurry from the inked paper product; flowing theslurry onto a surface of a semi-permeable conveyor having pores ofsufficient size to pass the inked particles and retain the paper producton the surface of the conveyor; establishing a pressure differentialacross the conveyor to form a mat from the slurry; and showering the matwith liquid to break the mat and separate the ink particles from thepaper product.

It is preferable that the step of establishing a pressure differentialto form a mat occurs both before and after the step of showering themat. It is further preferable that the step of showering the mat occursin an area where substantially no pressure differential exists acrossthe conveyor. It is additionally preferable that the showering stepincludes preventing the flow of liquid through the conveyor in the areaof the paper product being showered.

To further achieve the foregoing objects, and in accordance with thepurposes of the invention as embodied and broadly described herein, anapparatus is provided for removing ink particles from an inked paperproduct comprising means for conveying the paper product along a path,the conveying means being constructed of a semi-permeable material thatpasses the ink particles while retaining the paper product; meansproximate to a first side of the conveying means for establishing apressure differential across the conveying means and across a firstsegment of the path to draw the ink particles from the paper productthrough the conveying means; means on a second side of the conveyingmeans for directing a liquid toward the conveying means and onto thepaper product as the product is advanced along a second segment of thepath; and means on the first side of the conveying means opposite theliquid directing means for substantially preventing the establishment ofa pressure differential across the conveying means and across the secondsegment of the path.

The means for establishing a pressure differential preferably includesat least two chambers separated by the means for substantiallypreventing the establishment of a pressure differential. The means forestablishing a pressure differential preferably includes at least onechamber, the chamber having an upstream end, a downstream end, and themeans for preventing the establishment of a pressure differentialpositioned intermediate and spaced from the ends. The means forsubstantially preventing the establishment of a pressure differentialpreferably comprises a surface on a member proximate to the conveyingmeans along the second segment of the path.

To additionally acheive the foregoing objects, and in accordance withthe purposes of the invention as embodied and broadly described herein,an apparatus is provided for removing ink particles from an inked paperproduct comprising means for conveying the paper product along a path,the conveying means being constructed of a semi-permeable material thatpasses the ink particles while retaining the paper product; meansproximate to a first side of the conveying means for establishing apressure differential across the conveying means and across a firstsegment of the path to draw the ink particles from the paper productthrough the conveying means; means on a second side of the conveyingmeans for directing a liquid toward the conveying means and onto thepaper product as the product is advanced along a second segment of thepath; means on the first side of the conveying means opposite the liquiddirecting means for substantially preventing flow through the conveyingmeans and across the second segment of the path.

The means for establishing a pressure differential preferably includesat least two chambers separated by the means for substantiallypreventing flow through the conveying means. The means for establishinga pressure differential preferably includes at least one chamber, thechamber having an upstream and a downstream end, and the means forpreventing flow through the conveying means positioned intermediate andspaced from the ends. The means for substantially preventing flowthrough the conveying means preferably comprises a surface on a memberproximate to the conveying means along the second segment of the path.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate a preferred embodiment of theinvention and, together with a general description of the inventiongiven above and the detailed description of the preferred embodimentgiven below, serve to explain the principles of the invention.

FIG. 1 is a cross-section view of an apparatus for removing inkparticles from an inked paper product incorporating the teachings of thepresent invention.

FIG. 2 is a perspective view of a portion of the apparatus shown in FIG.1 showing the arrangement of shower heads;

FIG. 3 is a perspective view of a portion of the apparatus shown in FIG.1 showing the arrangement of apertured plates and blocking members; and

FIG. 4 is a perspective view of a portion of the apparatus shown in FIG.1 showing the arrangement of blocking members.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Reference will now be made in detail to the present preferred embodimentof the invention as illustrated in the accompanying drawing.

In accordance with the present invention there is provided an apparatusfor removing ink particles from an inked paper product comprising meansfor conveying the paper product along a path, the conveying means beingconstructed of a semi-permeable material that passes the ink particleswhile retaining the paper product; means proximate to a first side ofthe conveying means for establishing a pressure differential across theconveying means and across the first segment of the path to draw the inkparticles from the paper product through the conveying means; means on asecond side of the conveying means for directing a liquid toward theconveying means and onto the paper product as the paper product isadvanced along a second segment of the path; and means on the first sideof the conveying means opposite the liquid directing meant forsubstantially preventing the establishment of a pressure differentialacross the conveying means and across the second segment of the path.

As shown in FIG. 1, there is illustratively provided an apparatus 10 forremoving ink particles from an inked paper product. The means forconveying the paper product preferably includes an endless conveyor belt12 which is propelled and supported along an endless path by rollers 14.One or more of rollers 14 is positively driven. The conveyor belt isconstructed of a semi-permeable material that passes the ink particleswhile retaining the paper product. An example of such a belt is theSpiralflex 79 made by Brandon Drying Fabrics Division of Columbia, S.C.Such a belt is a 30 mesh polymer weave having 30 threads per inch and iscurrently used in fabric drying processes. It is to be understood thatsuch a material and such a conveying means are the present preferredembodiment of the invention and that the invention is not limited toconveying means which are endless belts.

The means proximate to a first side of the conveying means forestablishing a pressure differential across the conveying means andacross a first segment of the path to draw the ink particles from thepaper product through the conveying means preferably includes vacuumchambers 16, 18 and 20. As shown in FIGS. 3 and 4, vacuum chambers 16,18 and 20 are substantially airtight chambers with the exception of anopen top area which includes apertured plates 21 that are covered byconveyor belt 12. Vacuum hoses 22, 24 and 26 are respectively attachedto vacuum chambers 16, 18 and 20 to create a partial vacuum in vacuumchambers 16, 18 and 20. This creates a pressure differential acrossconveyor belt 12 in the areas which overlie the open portion of vacuumchambers 16, 18 and 20.

Vacuum hoses 22, 24 and 26 also remove material from vacuum chambers 16,18 and 20 respectively to vats 28, 30 and 32, respectively. Vacuumchamber 16 has an upstream end wall 34 and a downstream end wall 36.Vacuum chamber 18 has an upstream end wall 38 and a downstream end wall40. Vacuum chamber 20 has an upstream end wall 42 and a downstream endwall 44.

The means on a second side of the conveying means for directing a liquidtoward the conveying means and onto the paper product as the paperproduct is advanced along a second segment of the path is preferably aseries of shower heads 46, 48, 50 and 52 which, as shown in FIG. 2,include conduits 47, 49, 51 and 53 extending transversely across thepath of conveyor belt 12 and spaced from the second side of conveyorbelt 12. Conduits 47, 49, 51 and 53 include a series of spaced nozzlesfor directing jets of liquid onto conveyor belt 12.

The means on the first side of the conveying means opposite the liquiddirecting means for substantially preventing the establishment of apressure differential across the conveying means and across the secondsegment of the path preferably include a series of first blockingmembers 54 and 56 and second blocking members 58 and 60. Byillustration, first blocking member 54 preferably includes a blockhaving a flat top surface which is positioned between or constitutes thestructure between end wall 36 of vacuum chamber 16 and end wall 38 ofvacuum chamber 18. In this manner, the surface of first blocking member54 which underlies and contacts the advancing conveyor belt 12 betweenend walls 36 and 38 prevents the establishment of a pressuredifferential across conveying means 12 in the area between end walls 36and 38. It is also in this area that the liquid from shower head 48 isdistributed toward the portion of conveyor belt 12 which overlies thefirst blocking member 54, namely, the area between end walls 36 and 38.

By illustration, second blocking member 58 preferably has a flat topsurface which underlies and contacts the first surface of the advancingconveyor belt 12 intermediate and spaced from upstream end wall 34 anddownstream end wall 36. Thus, second blocking member 58 prevents theestablishment of a pressure differential across conveyor belt 12 in thesegment overlying second blocking member 58 between second blockingmember end walls 62 and 64.

In such a manner, it is seen that the path of conveyor belt 12 isdivided into alternating first and second segments. The first segmentsare areas in which a pressure differential is established acrossconveyor belt 12. The second segments of the path are portions in whichthe establishment of a pressure differential across conveyor belt 12 isprevented by first blocking members 54 and 56 and second blockingmembers 58 and 60. As seen from FIG. 1, first segments include segments65 and 67 in vacuum chamber 16, segments 69 and 71 in vacuum chamber 18,and segment 73 in vacuum chamber 20. Second segments include secondsegment 66 intermediate vacuum chamber 16, second segment 68 betweenvacuum chambers 16 and 18, second segment 70 intermediate vacuum chamber18, and second segment 72 between vacuum chambers 18 and 20.

In accordance with the invention, the means for establishing a pressuredifferential preferably includes at least two chambers separated by themeans for substantially preventing the establishment of a pressuredifferential. As embodied in the figures, it is seen that the twochambers represented by vacuum chambers 16 and 18 are separated by meansfor substantially preventing the establishment of a pressuredifferential such as first blocking member 54. In addition, it is seenthat the two chambers such as vacuum chambers 18 and 20 are separated bymeans for substantially preventing the establishment of a pressuredifferential such as first blocking member 56.

In accordance with the present invention, the means for establishing apressure differential preferably includes at least one chamber, thechamber having upstream, downstream and the means for preventing theestablishment of a pressure differential intermediate and spaced fromthe ends. As shown in the drawing, a chamber such as vacuum chamber 16has an upstream end 34, a downstream end 36, and includes means forpreventing the establishment of a pressure differential intermediate andspaced from ends 34 and 36 such as second blocking member 66.

In accordance with the present invention, the means for establishing apressure differential preferably comprises the surface on a memberproximate to the conveying means along the second segment of the path.As shown in the drawing, the surface on a member proximate to theconveying means includes the upwardly facing surfaces of first blockingmembers 54 and 56 and second blocking members 58 and 60 which underlieconveyor belt 12.

Apparatus 10 also includes a head box 74 which is located at theupstream end of the conveyor belt 12. Head box 74 is used fordistributing a paper product slurry on conveyor belt 12. Apparatus 10 isalso provided with a foot box 76 at the downstream end of the path and adoctor blade 78. Footbox 76 gathers the paper product after it isremoved from conveyor belt 12 by doctor blade 78. A spreader 80 islocated at the upstream end of the path near head box 74 and includes aninclined plate extending across the transverse width of conveyor belt 12and spaced from conveyor belt 12 for forming a layer of paper product ofuniform thickness on conveyor belt 12.

It is seen from FIG. 1 that a variety of conduits, such as conduit 43,are provided so that liquid drawn off from a downstream vat 32 can berecycled for use in upstream shower heads 46 and 48 to conserve liquid.

In operation, the apparatus is used in the following manner. Inked paperproduct is formed into a slurry by a pulper which is not shown in thedrawing. The pulper forms no part of the invention. As known to thoseskilled in the art, a pulper has blades which chop paper into smallpieces in the presence of known chemicals to form a slurry. The slurryis poured into head box 74 and then flowed or extruded as a layer ontothe upstream end of conveyor belt 12. The layer is applied and formed toa uniform thickness transversely across the conveyor belt by spreader80. Throughout the whole process, conveyor belt 12 continually movesalong its endless path, carrying the paper product with it.

After being spread by spreader 80, the inked paper product in slurryform reaches first segment 65 of the path where it is subjected to apressure differential by vacuum chamber 16 relative to the standardatmospheric pressure. By establishing the pressure differential acrossthe conveyor at first segment 65, ink particles and liquid from theslurry are drawn through semi-permeable conveyor belt 12 into vacuumchamber 16, down vacuum hose 22 and into vat 28, leaving a mat ofsubstantially defluidized paper and residue ink on conveyor belt 12.

The paper product advances to second segment 66 overlying secondblocking member 58 which prevents or interrupts the establishment of apressure differential across conveyor belt 12. The paper product is alsoexposed to a shower of liquid from shower head 46 while in secondsegment 66 of the path. Second blocking member 58 also substantiallyprevents flow through conveyor belt 12 in the area of second segment 66of the path because the top surface of second blocking member 58effectively blocks the pores of conveyor belt 12 in this area.Therefore, the paper product which arrives at second segment 66 in matform is broken up and formed into at slurry by the liquid supplied fromshower head 46. During this step in the process, the mat is broken upand again formed into a slurry, thus allowing the residue ink particlesto separate from the paper and be suspended in the liquid of the slurrymix.

The paper product in its slurry form then advances to first segment 67where it is exposed to a pressure differential which draws the liquidand the suspended ink particles from the slurry into vacuum chamber 16and which again forms a substantially defluidized mat from the slurry.The alternating process of forming a mat on first segments of the pathand breaking the mat and forming a slurry on the second segments of thepath continues as the paper product moves downstream along the path.

It is noted that the number of vacuum chambers and the relative numberof first and second blocking members may be altered. For instance, it ispossible to have a design in which two second blocking members arestationed within a single vacuum chamber, each paired with a showerhead.

In addition, it is seen that the pressure of the liquid from the showerhead, the distance between the shower head and the conveyor belt, andthe pressure of the vacuum in the vacuum chambers can be varied inaccordance with producing mats of varying thicknesses. For instance, itis possible to produce a mat having a thickness of 1/2 inch by using ashower pressure of 20-30 pounds per square inch, a vacuum of 8-10 inchesof mercury, and a placement of the shower heads eight inches from theconveyor belt. Also, as presently preferred, the conveyor belt isapproximately 45 feet long and 80 inches wide to produce a path betweenthe upstream and the downstream ends of about 20 feet in length.Additionally, as presently preferred, the longitudinal width of firstblocking members 54 and 56 and second blocking members 58 and 60 isapproximately 4 to 5 inches. Namely, the distance between walls 62 and64 a well as between walls 36 and 38 is approximately 4 to 5 inches. Aswith the other parameters of the apparatus, this parameter also may bevaried to ensure maximum deinking of the paper.

It is to be noted that the mat formed of the paper product over vacuumchamber 20 is removed from conveyor belt 12 by doctor blade 78 andgathered in foot box 76.

Also, as shown in FIG. 2, guide rails 82 are provided along both sidesof the coveyor belt to maintain the lateral limits of the paper productgenerally within the confines of conveyor belt 12.

In accordance with the present invention, there is also provided anapparatus for removing ink particles from an inked paper productcomprising means for conveying the paper product along a path, theconveying means being constructed of a semi-permeable material thatpasses the ink particles while retaining the paper product; meansproximate to a first side of the conveying means for establishing apressure differential across the conveying means and across the firstsegment of the path to draw the ink particles from the paper productthrough the conveying means; means on a second side of the conveyingmeans for directing a liquid toward the conveying means and onto thepaper product as the paper product is advanced along a second segment ofthe path; and means on the first side of the conveying means oppositethe liquid directing means for substantially preventing flow through theconveying means and across the second segment of the path.

As discussed above, and as illustratively shown in the Figures, themeans for conveying includes endless conveyor belt 12, the means forestablishing a pressure differential across the conveying means includesvacuum chambers 16, 18, and 20, the means for directing a liquid towardsthe conveying means includes shower heads 46, 48, 50 and 52. The meansfor substantially preventing flow through the conveying means includesfirst blocking members 54 and 56 and second blocking member 58 and 60.These blocking members prevent flow through conveyor belt 12 in the areaof second segments 66, 68, 70 and 72 because the blocking memberspreferably include a surface which underlies conveyor belt 12 in thearea of the second segments and blocks the flow of ink particles andliquid in the area of the second segment.

In accordance with the present invention there is provided a process forremoving ink particles from the inked paper product comprising: forminga slurry from the inked paper product; flowing the slurry onto a surfaceof a semi-permeable conveyor having pores of sufficient size to pass theink particles and retain the paper product on the surface of theconveyor; establishing a pressure differential across the conveyor toform a mat from the slurry; and showering the mat with liquid to breakthe mat and separate the ink particles from the paper product.

The step of forming a slurry from the inked paper product is known andforms no part of the invention. Therefore it will not be discussed infurther detail here. As described above, the step of flowing the slurryonto the surface of conveyor belt 12 includes loading an inked paperproduct in a slurry state into head box 74 so that it flows onto theupstream end 84 of conveyor belt 12 and is applied and spread to auniform thickness by stationary blade spreader 80 which forms aconverging path for the slurry as it progresses downstream toward thedownstream end 86 of conveyor belt 12.

The pressure differential is established across conveyor belt 12 byvacuum chamber 16, 18 and 20 as described above. Liquid and inkparticles from the slurry are passed through semi-permeable conveyorbelt 12 and the paper product is retained on the surface of conveyorbelt 12 in a mat form having a greater structural integrity and muchless water than the paper product in a slurry state.

The showering step includes showering the paper product which arrives ina mat state with a liquid which is preferably water so as to break themat, reduce its structural integrity, increase the concentration ofwater and separate the ink particles from the paper product intransforming the paper product in the mat state into a slurry state. Itis preferable to form a pressure differential across conveyor belt 12both before and after the step of showering the mat in order to moreeffectively separate the ink particles from the paper product and removethe particles from the paper product by drawing them throughsemi-permeable conveyor belt 12.

As noted above, it is preferable that the step of showering the matoccurs in an area where substantially no pressure differential existsacross the conveyor. This is in the area of second segments 66, 68, 70and 72 which lie above first blocking members 54 and 56 and secondblocking members 58 and 60. In addition, it is preferred that theshowering step includes preventing the flow of liquid through theconveyor in the area of the paper product being showered. As notedabove, this is also accomplished by first blocking members 54, 56 andsecond blocking members 58, 60.

It is noted that it is preferable that the liquid used in the process iswater. Also, it is preferable that the process is performed on acontinuously moving conveying surface disposed in a substantiallyhorizontal plane as shown in FIG. 1. Additionally, it is preferable thatthe showering step is performed by a liquid flowing through a pluralityof linearly arranged nozzles so that the flow is in the form ofplurality of fluid jets substantially perpendicular to the conveyorsurface as shown in FIG. 1 to aid in effectively breaking the mat.

Finally, it is noted that the disclosed process and apparatus removesash from the paper product while removing ink particles. As known tothose having skill in the art, ash is used as a filler between paperfibers for producing characteristics which are desirable in some paperproducts. Therefore, it is necessary to add ash when manufacturing suchpaper products from the end product of the disclosed process andapparatus.

Additional advantages and modifications will readily occur to thoseskilled in the art. The invention in its broader aspects is, therefore,not limited to the specific details, representative apparatus andillustrative examples shown and described. Accordingly departures may bemade from such details without departing from the scope or spirit ofapplicant's general inventive concept.

What is claimed is:
 1. An apparatus for removing ink particles from aninked paper product comprising:means for conveying the paper productalong a path, said conveying means being constructed of a semi-permeablematerial that passes the ink particles while retaining the paperproduct; means proximate to a first side of the conveying means forestablishing a pressure differential across the conveying means andacross a first segment of said path to draw the ink particles from thepaper product through said conveying means; means on a second side ofthe conveying means for directing a liquid toward the conveying meansand onto the paper product to break the paper product into a slurry asthe paper product is advanced along a second substantial segment of saidpath; and means on the first side of the conveying means directlyopposite the liquid directing means for substantially preventing theestablishment of a pressure differential across and flow through theconveying means and across the second substantial segment of the path.2. The apparatus of claim 1 wherein the means for establishing apressure differential includes at least two chambers separated by saidmeans for substantially preventing the establishment of a pressuredifferential and flow.
 3. The apparatus of claim 1 wherein the means forestablishing a pressure differential includes at least one chamber, saidchamber having an upstream end, a downstream end, and said means forsubstantially preventing the establishment of a pressure differentialand flow is positioned intermediate and spaced from said ends.
 4. Theapparatus of claim 1 wherein the means for substantially preventing theestablishment of a pressure differential and flow comprises a surface ona member proximate to the conveying means along the second segment ofthe path.
 5. The apparatus of claim 1 including spreader means forapplying and forming a slurry of uniform thickness transversely acrossthe conveying means.